Today, the United States has more than a thousand casinos and the number is increasing as more states legalize casino gambling. As of 2017, 40 states have legalized casino gaming. The legalization of casinos is due in part to Interstate competition, but the popularity of casinos has also spread to smaller towns and cities. The Las Vegas Valley is home to the largest concentration of casinos in the U.S., followed by Atlantic City, Chicago region, and other large metropolitan areas.

As casinos continue to evolve, they have become much more sophisticated. In order to retain customers, they have implemented a variety of technological innovations. The casinos are now regularly monitored through video cameras and computers. Many casino games have built-in microcircuitry. These systems enable the casinos to monitor and reward the bets of high rollers minute by minute. Other casino amenities include free show tickets, cheap buffets, and even comps. These programs have helped to increase the revenue of these casinos and the hotel industry.

During the 1990s, casinos started incorporating technological innovations into their operations. In addition to video cameras, computers and other security devices are routinely used to monitor game play. Chip-tracking chips are also used, which involve inserting a microcircuitry into a betting chip. This allows the casino to monitor the wagers minute by minute. In addition, roulette wheels are regularly monitored to determine statistical deviations and track customer behavior.